JP2019023436A - Diaphragm pump, ink supply system, and inkjet printer - Google Patents

Abstract

To provide a diaphragm pump in which liquid sending ability does not easily deteriorate.SOLUTION: A diaphragm pump P1 according to the invention includes: a pump chamber 125; a diaphragm 140; and a diaphragm deformation mechanism 135. The pump chamber 125 is formed into a box shape in which at least an inflow port 125c, an outflow port 125d, and a diaphragm attachment port 125b are opened and includes an internal space 125e. The diaphragm 140 is formed by an elastically deformable member and is provided at the pump chamber 125 so as to cover the diaphragm attachment port 125b. The diaphragm deformation mechanism 135 changes a cubic volume of the internal space 125e by elastically deforming the diaphragm 140. The outflow port 125d is provided at a highest position in the internal space 125e of the pump chamber 125.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a diaphragm pump, an ink supply system including the diaphragm pump, and an ink jet printer including the ink supply system.

  Conventionally, a diaphragm pump is known as one of small pumps. For example, Patent Document 1 discloses a small diaphragm pump including a valve forming body that achieves both sealing performance and flow rate accuracy. Diaphragm pumps are used in various devices having a mechanism for delivering liquid, and are also used in ink jet printers. In an ink jet printer, a diaphragm pump is used as a pump for supplying ink from an ink tank to an ink head, for example.

JP 2009-47121 A

  By the way, in general, a volume-variable pump such as a diaphragm pump has a lower delivery capability when gas is mixed into the liquid to be delivered. The volume-variable pump is a pump that delivers liquid by varying the volume of the internal space of the pump chamber. However, when gas is mixed into the liquid to be delivered, the change in the volume of the pump chamber is partially absorbed by the change in the volume of the gas, and the delivery amount of the liquid is reduced. Volumetric pumps are based on the premise that the fluid to be delivered is an incompressible fluid such as water or ink. If a compressible fluid such as air enters the incompressible fluid, the volume of the compressible fluid The liquid feeding capacity is reduced by the amount of change. Depending on the amount of air mixed in, the liquid may not be sent.

  As described above, the diaphragm pump is also used in an ink supply system of an ink jet printer. In an ink supply system of an ink jet printer, air sucked from the nozzles of the ink head may enter the diaphragm pump. This is because the ink pressure is kept negative so that the ink does not drip from the nozzles. In an ink supply system of an ink jet printer, it can be considered that air enters the inside of the diaphragm pump and lowers the liquid feeding capacity of the diaphragm pump. In addition to air mixing into the liquid, for example, there is a case where the liquid feeding capacity is lowered due to, for example, deterioration of the diaphragm and lowering of rigidity.

  This invention is made | formed in view of the point which concerns, The objective is to provide the diaphragm pump with which liquid feeding capability is hard to fall. Another object of the present invention is to provide an ink supply system and an ink jet printer provided with such a diaphragm pump.

  The diaphragm pump according to the present invention includes a pump chamber, a diaphragm, and a diaphragm deformation mechanism. The pump chamber is formed in a box shape in which at least an inflow port from which liquid flows in, an outflow port from which liquid flows out, and a diaphragm attachment port are opened, and includes an internal space. The diaphragm is formed of an elastically deformable member, and is provided in the pump chamber so as to cover the diaphragm attachment port. The diaphragm deformation mechanism is connected to the diaphragm from the outside of the pump chamber, and changes the volume of the internal space by elastically deforming the diaphragm. The outlet is provided at the highest position in the internal space of the pump chamber.

  According to the diaphragm pump, the air mixed into the pump chamber from the inlet gathers in the vicinity of the outlet provided at the highest position in the pump chamber. Therefore, the air is immediately discharged from the pump chamber by the driving of the diaphragm pump, and hardly affects the discharge capacity of the diaphragm pump. Thus, according to the diaphragm pump, it is possible to continue liquid feeding without reducing the discharge capacity even under conditions where air is mixed into the liquid.

1 is a front view of a printer according to an embodiment. It is a schematic diagram which shows an ink supply system. It is a perspective view of an upstream pump. It is a perspective view of an upstream pump, Comprising: It is the figure by which the 1st member, the 2nd member, and the 3rd member were decomposed | disassembled. It is a VV cross section in FIG. It is a schematic diagram which shows the longitudinal cross-section of a diaphragm.

  Hereinafter, embodiments of an ink supply system including a diaphragm pump according to the present invention and an ink jet printer including the ink supply system will be described with reference to the drawings. It should be noted that the embodiments described herein are not intended to limit the present invention. In addition, members / parts having the same action are denoted by the same reference numerals, and overlapping descriptions are omitted or simplified as appropriate.

  FIG. 1 is a front view of an ink jet printer (hereinafter referred to as a printer) 10 according to an embodiment. The printer 10 is an ink jet printer. In the following description, symbols F, Rr, L, R, U, and D in the drawings mean front, rear, left, right, upper, and lower when the printer 10 is viewed from the front. However, the above direction is only a direction determined for convenience of description, and does not limit the installation mode of the printer 10 at all.

  As shown in FIG. 1, the printer 10 performs printing on the recording medium 5. In the present embodiment, the recording medium 5 is a roll-shaped recording paper. However, the recording medium 5 is not limited to roll-shaped recording paper. For example, the recording medium 5 may be a resin sheet. The recording medium 5 is not limited to a flexible sheet, and may be a hard medium such as a glass substrate. In the present embodiment, the material forming the recording medium 5 is not particularly limited.

  The printer 10 according to the present embodiment includes a printer main body 12 and a guide rail 22 fixed to the printer main body 12. The guide rail 22 extends in the left-right direction, and a carriage 24 is engaged with the guide rail 22. The carriage 24 can slide left and right along the guide rail 22. An endless belt 25 is fixed to the carriage 24. Pulleys 23a and 23b are provided on the left end side and the right end side of the guide rail 22, respectively, and a carriage motor 26 is connected to the right pulley 23b. The pulley 23 b connected to the carriage motor 26 rotates by driving the carriage motor 26. A belt 25 is wound around the pulleys 23a and 23b. When the carriage 25 is driven by driving the carriage motor 26 and rotating the pulley 23b, the carriage 24 moves in the left-right direction. As described above, the carriage 24 is configured to be movable in the left-right direction along the guide rail 22.

  The printer main body 12 is provided with a platen 14 on which the recording medium 5 is placed. The platen 14 is a member that supports the recording medium 5 when printing is performed on the recording medium 5. The platen 14 is provided with a pair of upper and lower grit rollers 16 and a pinch roller 17. A feed motor 18 is connected to the grit roller 16. The grit roller 16 is rotationally driven by a feed motor 18. The recording medium 5 is conveyed in the front-rear direction when the grit roller 16 rotates while being sandwiched between the grit roller 16 and the pinch roller 17.

  The printer 10 according to the present embodiment has a plurality of ink supply systems. FIG. 2 is a schematic diagram showing the ink supply system 30 and the capping system 60. The ink supply system 30 is a system that supplies ink from the ink tank 34 toward the ink head 32. The ink supply system 30 is provided for each ink head 32. One ink supply system 30 has one ink tank 34. The printer 10 according to the present embodiment includes a plurality of ink heads 32 and the same number of ink supply systems 30 as the ink heads 32. The number of ink heads 32 and ink supply systems 30 is not particularly limited. The plurality of ink supply systems 30 have the same configuration. Therefore, hereinafter, the configuration of one ink supply system 30 will be described in detail.

  As shown in FIG. 2, the ink supply system 30 according to the present embodiment includes an ink head 32, an ink tank 34, an introduction channel 40, an upstream channel 42u, a downstream channel 42d, and an upstream side. The pump P1, the downstream pump P2, the upstream damper 50, the downstream damper 52, the introduction valve 54, the circulation valve 56, and the air trap 70 are provided. The ink supply system 30 according to this embodiment is an ink supply system that circulates ink in a flow path. Hereinafter, the annular flow path constituted by the upstream flow path 42u and the downstream flow path 42d may be referred to as a circulation flow path 42.

  As shown in FIG. 2, the ink head 32 is mounted on the carriage 24. The ink head 32 is movable in the left-right direction along the guide rail 22 via the carriage 24. The ink head 32 ejects ink onto the recording medium 5 placed on the platen 14. On the bottom surface of the ink head 32, a nozzle 32a for discharging ink is formed. Inside each ink head 32, an actuator (not shown) including a piezoelectric element or the like is provided. The actuator is electrically connected to the control device 80 (see FIG. 1). The actuator is controlled by the control device 80. When the actuator is driven, ink is ejected from the nozzle 32 a of the ink head 32 toward the recording medium 5.

  The ink tank 34 is a member that stores ink. The ink tank 34 is detachably provided on the printer main body 12. However, the position of the ink tank 34 is not particularly limited, and may be detachably provided on the carriage 24, for example. Examples of ink stored in one ink tank 34 include process color inks such as cyan ink, magenta ink, yellow ink, light cyan ink, light magenta ink, and black ink, and white ink, metallic ink, and clear ink. Special color ink. The type of ink stored in the ink tank 34 is not limited.

  The introduction flow path 40 is a flow path for supplying the ink stored in the ink tank 34 to the upstream flow path 42u. Therefore, the introduction flow path 40 has one end connected to the ink tank 34 and the other end connected to the upstream flow path 42u. An introduction valve 54 is provided in the middle of the introduction flow path 40. The introduction valve 54 is a valve that opens / closes the introduction flow path 40.

  The circulation channel 42 is an annular channel through which ink circulates, and is composed of an upstream channel 42u and a downstream channel 42d. One end of the upstream flow path 42 u is connected to the introduction flow path 40 at the connection portion CP, and the other end is connected to the ink head 32. The upstream flow path 42 u is a flow path for supplying ink to the ink head 32. The direction of the arrow shown in FIG. 2 is the direction of ink flow. The ink flow through the upstream flow path 42u is one-way in the direction of the arrow in FIG. In the upstream flow path 42u, an upstream pump P1 is disposed immediately downstream of the connection portion CP. An upstream damper 50 is provided downstream of the upstream pump P1, and an ink head 32 is provided further downstream of the upstream damper 50. On the other hand, a downstream flow path 42 d is connected to the downstream side of the ink head 32. The downstream channel 42d has an upstream side connected to the ink head 32 and a downstream side connected to a connection portion CP between the introduction channel 40 and the upstream channel 42u. In the connection part CP, the introduction flow path 40, the upstream flow path 42u, and the downstream flow path 42d are branched. In the downstream flow path 42d, a downstream damper 52, a downstream pump P2, an air trap 70, and a circulation valve 56 are provided in order from the upstream side. The ink flow flowing in one-way through the circulation flow path 42 including the upstream flow path 42u and the downstream flow path 42d is generated by the upstream pump P1 and the downstream pump P2. The circulation valve 56 is a valve that opens or closes the circulation flow path 42. When the circulation valve 56 is opened, the circulation channel 42 functions as a channel for circulating ink. On the other hand, when the circulation valve 56 is closed, the circulation flow path 42 forms a one-way flow path from the connection portion CP to the air trap 70 via the ink head 32.

  The types and materials of the introduction channel 40, the upstream channel 42u, and the downstream channel 42d are not limited. However, the introduction channel 40, the upstream channel 42u, and the downstream channel 42d have flexibility, for example. It is a tube.

  The upstream pump P1 and the downstream pump P2 are members for feeding ink. The upstream pump P <b> 1 is a pump for supplying ink toward the ink head 32, and adjusts the flow rate of ink flowing to the ink head 32. The downstream pump P <b> 2 is a pump for collecting ink from the ink head 32, and adjusts the flow rate of ink flowing out from the ink head 32. The upstream ink pressure is adjusted by adjusting the ink supply flow rate by the upstream pump P1. The downstream ink pressure is adjusted by adjusting the ink return flow rate by the downstream pump P2. The ink pressure in the ink head 32 is adjusted by adjusting the upstream and downstream ink pressures. In the present embodiment, the upstream pump P1 and the downstream pump P2 are the same diaphragm pump. The internal structure of the upstream pump P1 and the downstream pump P2 will be described later.

  The upstream damper 50 and the downstream damper 52 are mounted on the carriage 24. The upstream damper 50 and the downstream damper 52 are members for reducing the pressure fluctuation of the ink to stabilize the ink ejection operation of the ink head 32 and adjusting the ink pressure in the ink head 32 to a desired pressure. is there. The upstream damper 50 detects the pressure of the ink flowing into the upstream damper 50. The driving of the upstream pump P1 is controlled based on the pressure detection result by the upstream damper 50. The downstream damper 52 detects the pressure of the ink flowing into the downstream damper 52. The driving of the downstream pump P2 is controlled based on the pressure detection result by the downstream damper 52.

  The air trap 70 is provided downstream of the downstream pump P2 in the downstream channel 42d. The air trap 70 is a device that captures air contained in the ink. Air in the ink is mainly mixed from the ink head 32. The air trap 70 is a gas-liquid separator, for example. A discharge passage 44 is connected to the air trap 70. A discharge valve 58 is provided in the middle of the discharge flow path 44. The discharge valve 58 is a valve that opens / closes the discharge flow path 44. The discharge passage 44 is connected to the waste liquid tank 68 further beyond the discharge valve 58. Although the material and kind of the member which comprises the discharge flow path 44 are also not limited, the discharge flow path 44 is also a tube, for example.

  The printer 10 according to the present embodiment includes a capping system 60. The capping system 60 includes a cap 62, a cap moving mechanism 64, and a suction pump 66. The cap 62 and the suction pump 66 are disposed at a home position (not shown) located at the right end of the guide rail 22 (see FIG. 1). The home position is a position where the ink head 32 waits when printing is waiting, that is, when printing is not being performed. The cap 62 prevents the ink adhering to the nozzle 32a of the ink head 32 from being cured and clogging the nozzle 32a. The cap 62 is attached to the ink head 32 so as to cover the nozzles 32a of the ink head 32 during printing standby. The cap moving mechanism 64 is connected to the cap 62. The cap moving mechanism 64 is a mechanism that moves the cap 62 up and down toward the nozzle surface of the ink head 32 at the home position. The configuration of the cap moving mechanism 64 is not particularly limited, but includes, for example, a drive motor. The cap moving mechanism 64 moves the cap 62 up and down by driving the drive motor.

  The suction pump 66 is a member that sucks ink in the ink head 32 when the cap 62 is attached to the ink head 32. The suction is also an operation for preventing clogging of the nozzle 32 a of the ink head 32. The suction port of the suction pump 66 is connected to the cap 62. The discharge port of the suction pump 66 is connected to the waste liquid tank 68. The ink sucked by the suction pump 66 is discarded in the waste liquid tank 68.

  The control device 80 is a member that controls the operation of each unit. The controller 80 includes a carriage motor 26, a feed motor 18, actuators built in the ink head 32, an upstream pump P 1, a downstream pump P 2, an introduction valve 54, a circulation valve 56, a discharge valve 58, and a cap moving mechanism 64. A drive motor and a suction pump 66 are connected to control their movement. The control device 80 is connected to the upstream damper 50 and the downstream damper 52 and receives signals transmitted by them. The configuration of the control device 80 is not particularly limited. For example, the control device 80 is a computer, and may include a central processing unit (hereinafter referred to as a CPU), a ROM storing a program executed by the CPU, a RAM, and the like. Each unit of the control device 80 may be a processor or a circuit.

  In the print standby state, the control device 80 controls the cap moving mechanism 64 to attach the cap 62 to the ink head 32. The control device 80 controls the upstream pump P1 and the downstream pump P2 to circulate ink in the circulation flow path 42. The circulation is performed in order to prevent the pigment or the like from settling in the ink when the ink containing the pigment or the like is used. At the same time, the control device 80 controls the ink pressure in the ink head 32 within a predetermined pressure range by controlling the upstream ink pressure and the downstream ink pressure to a predetermined pressure. The ink pressure in the ink head 32 in the standby state is controlled to a pressure at which ink can be ejected and ink does not drip from the nozzle 32a. The pressure is, for example, a negative pressure of about −1 kPa as a gauge pressure.

  When printing, the cap 62 is separated from the ink head 32, and the ink head 32 is moved from the home position onto the platen 14 by driving the carriage motor 26. The ink head 32 is scanned in the left-right direction together with the carriage 24 while ejecting ink onto the recording medium 5 placed on the platen 14. At this time, the ejection timing of each nozzle 32a and the scanning of the carriage 24 are controlled in conjunction with each other. Thereby, printing of one printing line is performed. Thereafter, the recording medium 5 is fed forward by the grit roller 16 connected to the feed motor 18, and printing at the next position is performed.

  The ink supply system 30 according to the present embodiment is configured to be able to discharge ink in the circulation channel 42. When discharging ink, the control device 80 closes the circulation valve 56. Further, the introduction valve 54 and the discharge valve 58 are opened. By these valve operations, the flow from the ink tank 34 to the discharge flow path 44 and the waste liquid tank 68 via the introduction flow path 40, the upstream flow path 42u, the ink head 32, the downstream flow path 42d, and the air trap 70. A path is formed. Further, the control device 80 drives the upstream pump P1 and the downstream pump P2 to send the ink in the circulation channel 42 toward the waste liquid tank 68. Therefore, the sent ink is discarded in the waste liquid tank 68. The ink discharge as described above is performed when the ink is replaced or when the printer 10 is moved.

  Furthermore, the ink supply system 30 according to the present embodiment can suck ink from the nozzle 32 a toward the outside of the ink head 32. The cap 62 is attached to the ink head 32 during ink suction. The suction pump 66 sucks ink from the nozzle 32 a of the ink head 32 through the cap 62.

(Configuration of upstream pump and downstream pump)
The upstream pump P1 and the downstream pump P2 are members that circulate ink in the circulation flow path 42. As described above, in the present embodiment, the upstream pump P1 and the downstream pump P2 are the same diaphragm pump. Therefore, the internal structure and operation of the upstream pump P1 will be described below, and the description of the internal structure and operation of the downstream pump P2 will be omitted. FIG. 3 is a perspective view of the upstream pump P1 according to the present embodiment. As shown in FIG. 3, the upstream pump P <b> 1 includes a first member 110, a second member 120, and a third member 130. FIG. 4 is a perspective view of the upstream pump P1, in which the first member 110, the second member 120, and the third member 130 are disassembled. As shown in FIG. 4, the upstream pump P <b> 1 according to the present embodiment further includes a diaphragm 140, an inflow side valve 151, and an outflow side valve 152.

  The first member 110 is a rectangular member in plan view. The first member 110 is made of, for example, resin. However, the planar shape of the first member 110 may not be rectangular, and the material is not limited to resin. A suction port 111 and a discharge port 112 are formed in the first member 110. The suction port 111 and the discharge port 112 are members into which the tube of the upstream channel 42u is inserted. Specifically, a tube on the introduction flow path 40 (see FIG. 2) side of the upstream flow path 42u is attached to the suction port 111, and an upstream damper 50 (FIG. 2) of the upstream flow path 42u is attached to the discharge port 112. See) side tube is attached. The ink is sucked into the upstream pump P1 from the suction port 111, and sent out from the discharge port 112 through the upstream pump P1. 5 is a VV cross section in FIG. As shown in FIG. 5, the first component 110 includes a first inflow channel 113 that communicates with the suction port 111 and a first outflow channel 114 that communicates with the discharge port 112. The first inflow channel 113 and the first outflow channel 114 penetrate to the lower surface of the first component 110. Furthermore, the first component 110 includes a first inflow chamber 115 and a first outflow chamber 116 on the lower surface. The first inflow chamber 115 is a recess formed in the lower surface of the first member 110 and communicates with the first inflow channel 113. The first outflow chamber 116 is a recess formed in the lower surface of the first member 110 and communicates with the first outflow channel 114.

  The second member 120 forms an inflow side check mechanism 171 and an outflow side check mechanism 172 together with the first member 110, the inflow side valve 151, and the outflow side valve 152, and together with the third member 130 and the diaphragm 140. It is a member constituting the pumping mechanism 160. The details of the pumping mechanism 160, the inflow side check mechanism 171 and the outflow side check mechanism 172 will be described later. The second member 120 is also formed of, for example, resin. As shown in FIG. 5, the second member 120 includes a second inflow chamber 121 and a second outflow chamber 122 on the upper surface. The second inflow chamber 121 and the second outflow chamber 122 are recesses formed on the upper surface of the second member 120. A pump chamber 125 is formed on the lower surface of the second member 120. The pump chamber 125 is a recess formed on the lower surface of the second member 120. A second inflow channel 123 extends downward from the bottom surface of the second inflow chamber 121. The second inflow channel 123 is a through hole that penetrates from the bottom surface of the second inflow chamber 121 to the top surface 125 a of the pump chamber 125. Similarly, a second outflow channel 124 extends downward from the bottom surface of the second outflow chamber 122. The second outflow channel 124 is a through hole that penetrates from the bottom surface of the second outflow chamber 122 to the top surface 125 a of the pump chamber 125. Therefore, the pump chamber 125 has a lower surface opening 125b (hereinafter referred to as a diaphragm mounting opening 125b), an inflow side opening 125c through which the second inflow channel 123 penetrates, and an outflow side opening through which the second outflow channel 124 penetrates. Three openings of 125d are provided.

  The inflow side valve 151 and the outflow side valve 152 are made of, for example, rubber that can be elastically deformed. In the present embodiment, the inflow side valve 151 and the outflow side valve 152 are the same member. However, the inflow side valve 151 and the outflow side valve 152 may be different members. As shown in FIG. 4, the inflow side valve 151 includes a valve portion 151a and a seal portion 151b. In the inflow side check mechanism 171, the valve portion 151 a serves as a valve that allows the flow of ink only in the inflow direction from the outside into the upstream pump P <b> 1. In the inflow side valve 151, the seal portion 151b has an annular shape surrounding the valve portion 151a. The seal portion 151b serves to seal the outside of the inflow side check mechanism 171 when the first member 110 and the second member 120 are coupled. However, the seal portion 151b may not exist in the inflow side valve 151, and a seal member such as a gasket or an O-ring may be used separately instead. The outflow side valve 152 has the same configuration as the inflow side valve 151.

  The third member 130 is a member that sandwiches and fixes the diaphragm 140 with the second member 120 and elastically deforms the diaphragm 140. As shown in FIG. 5, the third member 130 includes a main body 131, a motor 132 (see FIG. 4), an eccentric cam 133, and a connecting rod 134. The main body 131 is made of, for example, resin. A diaphragm mounting groove 131a is formed in the main body 131. A diaphragm 140 is mounted in the diaphragm mounting groove 131a.

  The diaphragm 140 is a sheet-like member that can be elastically deformed. As shown in FIG. 5, when the third member 130 and the second member 120 are coupled, the diaphragm 140 is sandwiched and fixed by the diaphragm mounting groove 131 a and the second member 120. The diaphragm 140 according to the present embodiment is provided with a through hole at the center. Diaphragm 140 is a donut-shaped sheet in plan view. Details of the material and the like of the diaphragm 140 will be described later.

  A connecting rod 134 is fixed to the center of the diaphragm 140. The upper end of the connecting rod 134 according to the present embodiment protrudes above the diaphragm 140 through the center hole of the diaphragm 140. The upper end of the connecting rod 134 is composed of a fixing member 134d. The fixing member 134d is a member that couples the connecting rod 134 and the diaphragm 140 by sandwiching the diaphragm 140 with the connecting rod main body 134a. The fixing member 134d and the connecting rod main body 134a are press-fitted, for example. Near the lower end of the connecting rod 134, a cam receiving portion 134b is formed. The cam receiving portion 134b is a long hole that is long in the left-right direction. The inner peripheral portion 134c of the cam receiving portion 134b is formed of a sliding grade resin. The inner peripheral part 134c may be formed integrally with the connecting rod main body 134a, or may be provided with a separate part.

  As shown in FIG. 5, an eccentric cam 133 is inserted into the cam receiving portion 134b. The eccentric cam 133 is fixed to the rotating shaft 132 a of the motor 132. The eccentric cam 133 includes a circular outer peripheral portion 133a having a radius R1. The outer peripheral portion 133a is made of a sliding grade resin. Therefore, the inner peripheral portion 134c of the cam receiving portion 134b and the outer peripheral portion 133a of the eccentric cam 133 can be smoothly slid by contact between sliding grade resins. The eccentric cam 133 is coupled to the rotating shaft 132a of the motor 132 at a position deviated from the center of the outer peripheral portion 133a. The eccentric cam 133 rotates along with the rotation of the rotation shaft 132a. At that time, the eccentric cam 133 rotates while drawing a rotation trajectory having a radius R2. As the eccentric cam 133 rotates, the connecting rod 134 reciprocates in the vertical direction with an amplitude L1 represented by L1 = 2 × (R2−R1). The motor 132, the eccentric cam 133, and the connecting rod 134 constitute a diaphragm deformation mechanism 135 that elastically deforms the diaphragm 140 in the vertical direction.

  As shown in FIG. 4, the first member 110 and the third member 130 are coupled by tightening four screws 117 into the four screw holes 136, respectively. When the first member 110 and the third member 130 are coupled, the second member 120, the inflow side valve 151, the outflow side valve 152, and the diaphragm 140 are sandwiched therebetween. Thereby, the 2nd member 120, the inflow side valve 151, the outflow side valve 152, and the diaphragm 140 are fixed. By combining these members, a pumping mechanism 160, an inflow side check mechanism 171 and an outflow side check mechanism 172 are formed inside the upstream pump P1.

  The pumping mechanism 160 includes a pump chamber 125, a diaphragm 140, and a diaphragm deformation mechanism 135. As shown in FIG. 5, the diaphragm 140 is attached to the diaphragm attachment opening 125 b of the pump chamber 125 by being sandwiched between the second member 120 and the third member 130. The diaphragm mounting opening 125 b is covered with the diaphragm 140, whereby an internal space 125 e is formed in the pump chamber 125. The internal space 125 e is a space surrounded by the pump chamber 125 and the diaphragm 140.

  The inflow side check mechanism 171 includes a first inflow chamber 115, a second inflow chamber 121, and an inflow side valve 151. As shown in FIG. 5, when the first member 110 and the second member 120 are combined, the first inflow chamber 115 and the second inflow chamber 121 are combined so as to face each other to form an inflow chamber. In the inflow chamber, the inflow side valve 151 is fixed so as to cover the first inflow channel 113. Therefore, the inflow side valve 151 serves as a lid for the pressure from the pump chamber 125 side, and the liquid cannot move in the direction from the pump chamber 125 side to the suction port 111 side. On the other hand, the inflow side valve 151 is deformed when pressure from the suction port 111 side is applied, and opens the flow path. Accordingly, the liquid can move in the direction from the suction port 111 side toward the pump chamber 125 side. The inflow side check mechanism 171 thus constitutes a check mechanism that allows the liquid to move only from the suction port 111 side to the pump chamber 125 side.

  The outflow side check mechanism 172 is configured in the same manner as the inflow side check mechanism 171 except for the direction in which the liquid can move. The outflow side check mechanism 172 is configured to allow the liquid to move only from the pump chamber 125 side to the discharge port 112 side. The outflow side check mechanism 172 includes a first outflow chamber 116, a second outflow chamber 122, and an outflow side valve 152. When the first member 110 and the second member 120 are combined, the first outflow chamber 116 and the second outflow chamber 122 are combined to face each other to form an outflow chamber. In the outflow chamber, the outflow side valve 152 is fixed so as to cover the second outflow channel 124. The outflow side check mechanism 172 allows the liquid to move only from the pump chamber 125 side to the discharge port 112 side based on the same principle as the inflow side check mechanism 171. The inflow side check mechanism 171 and the outflow side check mechanism 172 move the liquid only in the direction from the suction port 111 to the discharge port 112 via the pump chamber 125.

  The pumping mechanism 160 reciprocates the diaphragm 140 up and down by rotating the motor 132. When the diaphragm 140 is reciprocated up and down, the volume of the internal space 125e increases or decreases accordingly. When the diaphragm 140 is elastically deformed upward and the volume of the internal space 125e is reduced, the outflow side check mechanism 172 is opened by the ink pressure, and the ink is sent out of the pump chamber 125 through the outflow side opening 125d. The delivered ink is discharged from the discharge port 112 to the outside of the upstream pump P1 via the second outflow channel 124 and the first outflow channel 114. Subsequently, when the diaphragm 140 is elastically deformed downward and the volume of the internal space 125e increases, the inflow side check mechanism 171 is opened by the negative pressure in the pump chamber 125, and the ink flows into the suction port 111 and the first inflow. It flows into the pump chamber 125 from the inflow side opening 125 c via the flow path 113 and the second inflow flow path 123. The upstream pump P1 repeats the above operation to send ink in the direction of the arrow in FIG. The control device 80 controls the rotation timing and the rotation speed of the motor 132 in response to a signal from the upstream damper 50.

(Decrease in liquid delivery volume due to air contamination)
By the way, in general, a volume-variable pump such as a diaphragm pump has a lower delivery capability when gas is mixed into the liquid to be delivered. As described for the upstream pump P1 according to the present embodiment, the volume-variable pump delivers liquid by changing the volume of the internal space of the pump chamber. However, when gas is mixed into the liquid to be delivered, the change in the volume of the pump chamber is partially absorbed by the change in the volume of the gas, and the delivery amount of the liquid decreases. The volume-variable pump is based on the premise that the fluid to be delivered is an incompressible fluid such as water or ink. Therefore, when a compressible fluid such as air is mixed into the incompressible fluid, the liquid feeding capability is reduced by the volume change of the compressible fluid.

  In an ink supply system of an ink jet printer, the ink pressure is kept at a negative pressure so that the ink does not drip from the nozzles. Therefore, there is a possibility that outside air is sucked from the nozzle. In particular, in a system that circulates ink in the circulation flow path, such as the ink supply system 30 according to the present embodiment, the possibility is high. Therefore, in the circulation type ink supply system, it is common to provide an air trap for capturing air in the circulation channel. Also in the ink supply system 30 according to the present embodiment, an air trap 70 is provided in the circulation channel 42. However, as can be understood from FIG. 2, the air sucked from the ink head 32 is not removed in a portion of the downstream side flow path 42 d on the upstream side of the air trap 70. Therefore, when air is taken in from the ink head 32, the air flows into the downstream pump P2. In addition, the air removal function of the air trap 70 may not be perfect, and ink containing air may flow into the upstream pump P1. Therefore, when a conventional diaphragm pump is used for the upstream pump P1 and the downstream pump P2, there is a high possibility that the amount of liquid fed will decrease due to the air mixed in the liquid to be fed. Depending on the amount of air mixed in, there is a possibility that the liquid cannot be fed.

  Therefore, the upstream pump P1 according to the present embodiment includes the outflow side opening 125d at the highest position in the pump chamber 125, as shown in FIG. Furthermore, the top surface 125a of the pump chamber 125 includes an inclined surface 125f. The inclined surface 125f is highest at the position of the outflow side opening 125d, and is inclined so as to become lower toward the inflow side opening 125c.

  When air enters the pump chamber 125, the air enters from the inflow side opening 125c. The intruded air has a specific gravity smaller than that of ink, and therefore gathers above the pump chamber 125. That is, the air that has entered collects in the vicinity of the outflow side opening 125d. Therefore, the air is immediately discharged from the pump chamber 125 by driving the diaphragm pump. Therefore, the air mixed in the ink hardly affects the discharge capacity of the diaphragm pump. As described above, according to the diaphragm pump according to the present embodiment, liquid feeding can be continued without substantially reducing the discharge capacity even under use conditions in which air is mixed into the ink.

  Furthermore, the upstream pump P <b> 1 according to this embodiment includes an inclined surface 125 f on the top surface 125 a of the pump chamber 125. The inclined surface 125f extends downward from the outflow side opening 125d. Therefore, the air that once floats from the ink in the pump chamber 125 and comes into contact with the inclined surface 125f travels toward the outflow side opening 125d along the inclined surface 125f. The upstream pump P1 according to the present embodiment includes the inclined surface 125f on the top surface 125a of the pump chamber 125, so that the air mixed in the ink can be efficiently collected near the outflow side opening 125d. Therefore, the air mixed in the ink can be efficiently discharged from the pump chamber 125. In FIG. 5, the inclined surface 125f is a flat surface, but may be a curved surface.

  The top surface 125a of the pump chamber 125 includes a second inclined surface 125g on the opposite side of the inclined surface 125f across the outflow side opening 125d. Thus, the top surface 125a of the pump chamber 125 may include a plurality of inclined surfaces. The second inclined surface 125g guides the air reaching the left side of the outflow side opening 125d toward the outflow side opening 125d. When the top surface 125a includes a plurality of inclined surfaces, the outflow side opening 125d may not be formed at one end of the pump chamber 125, and may be formed, for example, near the center of the top surface 125a.

  An inflow side opening 125c is opened near the right end of the inclined surface 125f. The inflow side opening 125c is formed in the middle of the inclined surface 125f. Air enters the pump chamber 125 from the inflow side opening 125c. Since the inflow side opening 125c is formed in the inclined surface 125f, air is more efficiently guided to the vicinity of the outflow side opening 125d.

  As described above, the upstream side pump P1 according to the present embodiment is provided with the outflow side opening 125d as the liquid outlet at the highest position in the pump chamber 125 and the inclined surface that guides air to the outflow side opening 125d. 125f is provided so that air that has entered the pump chamber 125 can be quickly discharged. Furthermore, an inflow side opening 125c that is a liquid inlet is provided in the inclined surface 125f so that air can be discharged more efficiently. Since the air that has entered the pump chamber 125 is quickly discharged, the discharge capacity of the pump is hardly impaired.

(Decrease in liquid delivery due to deterioration)
In the diaphragm pump, there is a factor that lowers the liquid feeding capacity in addition to the intrusion of air into the pump chamber. One of them is the deterioration of the diaphragm. The diaphragm is configured to have appropriate elasticity and rigidity for liquid feeding. In the diaphragm pump, since the volume of the pump chamber is changed by elastic deformation of the diaphragm, the elasticity of the diaphragm is essential. On the other hand, when the rigidity of the diaphragm is weak, the diaphragm is extended by the pressure of the liquid to be supplied, and the amount of liquid supplied is reduced by the extension. Therefore, the diaphragm is adjusted in advance so as to have appropriate elasticity and rigidity.

  The rigidity of the diaphragm is imparted, for example, by applying a coating on the surface of the diaphragm. The coating is made of, for example, a fluororesin. If a fluororesin coating is applied to the surface of the diaphragm, chemical resistance is improved, it can be used for many chemicals, and rigidity can be given to the diaphragm, so this method is generally used. However, in a diaphragm pump using such a diaphragm, due to the elastic deformation of the diaphragm, the rigidity of the coating surface becomes weaker with use, and the discharge amount decreases rapidly from a certain stage.

  FIG. 6 is a schematic diagram showing a longitudinal section of the diaphragm 140. As shown in FIG. 6, the diaphragm 140 according to the present embodiment is formed by joining three donut-shaped sheets. Specifically, the diaphragm 140 includes a first sheet 140a, a second sheet 140b, and a reinforcing sheet 140c. The first sheet 140a and the second sheet 140b are the same member. The material of the first sheet 140a and the second sheet 140b is, for example, elastically deformable rubber. The first sheet 140a and the second sheet 140b constitute an upper surface and a lower surface of the diaphragm 140. Here, the first sheet 140a constitutes the upper surface of the diaphragm 140 and the second sheet 140b constitutes the lower surface of the diaphragm 140, but the reverse may be possible. The diaphragm 140 is a vertically symmetrical sheet. However, the diaphragm 140 may be configured such that there is an upper and lower distinction, or the first sheet 140a and the second sheet 140b may be different members.

  The reinforcing sheet 140c is sandwiched between the first sheet 140a and the second sheet 140b. The reinforcing sheet 140 c is a member for imparting rigidity to the diaphragm 140. The reinforcing sheet 140c is formed of, for example, a cloth having rigidity. However, the reinforcing sheet 140c may not be a cloth, and may be a thin metal plate, for example. The reinforcing sheet 140c suppresses the expansion of the diaphragm 140 due to the liquid pressure. Unlike the coating, the reinforcing sheet 140c does not change its rigidity even when the diaphragm 140 is repeatedly deformed, and is strong against deterioration over time. The upstream pump P1 according to the present embodiment can maintain the discharge amount even when used for a long time by the diaphragm 140 sandwiching the reinforcing sheet 140c as described above.

  Further, as shown in FIG. 5, the upstream pump P <b> 1 according to the present embodiment is configured not to bring the diaphragm 140 into contact with the top surface 125 a of the pump chamber 125. FIG. 5 is a diagram illustrating a state in which the diaphragm 140 is closest to the top surface 125 a of the pump chamber 125. Even in the state of FIG. 5, there is a gap between the diaphragm 140 and the top surface 125 a of the pump chamber 125. By preventing the diaphragm 140 from coming into contact with the top surface 125a of the pump chamber 125 during the reciprocating motion, wear and damage of the diaphragm 140 can be suppressed. By suppressing the wear and damage of the diaphragm 140, it is possible to suppress a decrease in the discharge amount due to aged deterioration.

  In addition, the cost reduction of a diaphragm pump is mentioned as a secondary effect of the structure which does not contact the diaphragm 140 and the top | upper surface 125a of the pump chamber 125. FIG. Since the diaphragm 140 does not come into contact with other members during the reciprocating motion, the diaphragm deformation mechanism 135 (the motor 132, the eccentric cam 133, and the connecting rod 134) is not required to have high mechanical strength. Normally, a bearing or the like is used as a mechanism for converting the rotational movement of the motor 132 into the reciprocating movement of the connecting rod 134, but the upstream pump P1 according to the present embodiment uses a sliding grade resin. The rotational motion transmission unit made of resin does not have much mechanical strength, but the cost is low. The cost of the diaphragm pump can be suppressed by adopting a transmission portion made of resin instead of a bearing or the like.

(Effect of this embodiment)
As described above, the diaphragm pump according to the present embodiment is configured such that the outflow side opening 125d communicating with the discharge port 112 is provided at the highest position of the pump chamber 125, and the air collected there is immediately discharged. ing. Moreover, the top surface 125a of the pump chamber 125 includes an inclined surface 125f extending downward from the outflow side opening 125d, and is configured to efficiently collect air near the outflow side opening 125d. Furthermore, the inflow side opening 125c communicating with the suction port 111 is opened in the inclined surface 125f, and the air entering from the inflow side opening 125c is more efficiently collected near the outflow side opening 125d. Since the diaphragm pump according to the present embodiment can discharge air immediately even if air enters the pump chamber 125, there is almost no decrease in the discharge amount due to air intrusion.

  In addition, the diaphragm pump according to the present embodiment includes the diaphragm 140 having a structure in which the reinforcing sheet 140c is sandwiched between the rubber first sheet 140a and the second sheet 140b, and suppresses a decrease in the discharge amount due to aging of the diaphragm. doing. Due to the reinforcing sheet 140c, the diaphragm 140 according to the present embodiment does not change in rigidity relatively even when used for a long time, and does not significantly reduce the pumping amount.

  Furthermore, since the diaphragm pump according to the present embodiment does not bring the diaphragm 140 into contact with the pump chamber 125, the diaphragm 140 is hardly worn or damaged. Therefore, it is possible to suppress a decrease in the discharge amount due to wear and damage of the diaphragm 140. Since the diaphragm 140 does not contact the pump chamber 125, it is not necessary to give the diaphragm deforming mechanism 135 high mechanical strength, and the cost can be reduced. In the present embodiment, the cost is reduced by using resin for the sliding portion of the diaphragm deformation mechanism 135.

  The diaphragm pump described above is particularly effective in a circulation type ink supply system and an ink jet printer provided with such an ink supply system. In the circulation type ink supply system, the ink is circulated in order to prevent sedimentation of pigments and the like in the ink. Therefore, air is easily sucked from the ink head. According to the diaphragm pump described above, liquid feeding can be continued with almost no influence even if air enters the pump chamber.

  The preferred embodiment has been described above. However, the diaphragm pump according to the present invention, the ink supply system including the diaphragm pump, and the ink jet printer including the ink supply system are not limited to the above-described embodiments.

  For example, the diaphragm pump according to the present invention is not limited to an ink supply system of an ink jet printer, and can be used in various other applications. Further, the ink supply system according to the present invention is not limited to the one mounted on the ink jet printer, and can be applied to all apparatuses for ejecting ink, for example, a powder curing type three-dimensional modeling apparatus.

  In the above-described embodiment, the liquid inlet to the pump chamber and the liquid outlet from the pump chamber are arranged in the horizontal direction, but the present invention is not limited to this. For example, in the pump chamber, the inlet may be provided below and the outlet may be provided above. The position and orientation of the diaphragm mounting opening are not limited to the above-described embodiment. The diaphragm attachment opening may be opened vertically, for example. Further, it does not have to face the top surface of the pump chamber. Arrangement | positioning of the inflow port in a pump chamber, an outflow port, and a diaphragm attachment opening is not limited except that an outflow port is arrange | positioned in the highest position.

  In the above-described embodiment, the diaphragm deformation mechanism includes the connecting rod that reciprocates, but is not limited to such a mechanism. Any mechanism that elastically deforms the diaphragm can be used as the diaphragm deformation mechanism. For example, the diaphragm can be elastically deformed by the cam itself. Also, the cam mechanism is not necessarily required when converting the rotation into the reciprocating motion. For example, a crank mechanism or the like can be used as a mechanism for converting rotation into reciprocating motion.

  In the above-described embodiment, the diaphragm pump includes the check mechanisms on the inflow side and the outflow side, respectively. However, the check mechanism may be provided outside the pump. For example, even if check valves are provided on the upstream side and the downstream side of the upstream pump P1 and the upstream side and the downstream side of the downstream pump P2 in the circulation channel 42 of FIG. Can be performed. The check mechanism is not limited to the above-described structure, and various check mechanisms such as a mechanism using a mechanical valve configured to open only on one side can be used.

  The material forming each part of the diaphragm pump is not limited to the above. For example, the first member, the second member, and the third member may be made of a metal, such as an aluminum alloy. The first sheet and the second sheet of the diaphragm need not be made of rubber, and may be other various elastic materials. The reinforcing sheet of the diaphragm does not need to be cloth or metal, and may be resin, for example.

  In the above-described embodiment, the diaphragm pump has a structure in which the first member, the second member, and the third member are combined and an elastic diaphragm or the like is sandwiched therebetween, but is not limited thereto. The specific structure for forming the components of the diaphragm pump is not limited.

  The arrangement of the members in the circulation channel of the ink supply system is not limited to the above-described embodiment. The arrangement of the members in the circulation channel can be changed as appropriate, and the members can be added as appropriate. In addition, the ink supply system according to the present invention is not limited to a system that includes a circulation channel and circulates ink in the circulation channel. For example, a system in which ink is linearly supplied from an ink tank to an ink head. It may be. The diaphragm pump according to the present invention can be applied to any known ink supply system including a pump.

  The ink supply system according to the present invention includes, for example, various continuous methods such as a binary deflection method or a continuous deflection method, and various on-demand methods such as a piezo drive method and a thermal method. Is available. The ink ejection method according to the present invention is not limited.

5 Recording medium 10 Printer (inkjet printer)
30 Ink supply system 32 Ink head 34 Ink tank 40 Introduction flow path 42u Upstream flow path 42d Downstream flow path 125 Pump chamber 125b Diaphragm attachment opening (diaphragm attachment opening)
125c Inlet side opening (inlet)
125d Outlet opening (outlet)
125f Inclined surface 132 Motor 133 Eccentric cam (cam)
134 Connecting rod 135 Diaphragm deformation mechanism 140 Diaphragm P1 Upstream pump P2 Downstream pump

Claims (9)

A pump chamber having an internal space formed in a box shape having at least an inflow port from which liquid flows in, an outflow port from which liquid flows out, and a diaphragm mounting port;
A diaphragm formed by an elastically deformable member and provided in the pump chamber so as to cover the diaphragm mounting port;
A diaphragm deformation mechanism that is connected to the diaphragm from the outside of the pump chamber and changes the volume of the internal space by elastically deforming the diaphragm;
With
The outlet is provided at the highest position in the internal space of the pump chamber.
Diaphragm pump. The pump chamber includes a top surface provided with the outlet.
The top surface includes an inclined surface extending downward from the outlet on the inner space side.
The diaphragm pump according to claim 1. The inflow port is provided on the inclined surface,
The diaphragm pump according to claim 2. The pump chamber includes a first inner wall surface facing the diaphragm on the inner space side,
The diaphragm deformation mechanism elastically deforms the diaphragm so that a gap is formed between the diaphragm and the first inner wall surface even when the diaphragm and the first inner wall surface are closest to each other.
The diaphragm pump as described in any one of Claims 1-3. The diaphragm deformation mechanism is
A motor with a rotating shaft;
A cam fixed to the rotating shaft and rotating together with the rotating shaft;
A connecting rod that reciprocates in a first direction in response to rotation of the cam;
With
The connecting rod is fixed to the diaphragm and elastically deforms the diaphragm in the first direction;
The diaphragm pump as described in any one of Claims 1-4. The cam includes an outer peripheral portion made of resin,
The connecting rod has an inner peripheral portion in contact with an outer peripheral portion of the cam, and includes a cam receiving portion in which the inner peripheral portion is formed of a resin.
The diaphragm pump according to claim 5. The diaphragm includes a first sheet formed of an elastic body, a second sheet formed of an elastic body, and a reinforcing member sandwiched between the first sheet and the second sheet.
The diaphragm pump as described in any one of Claims 1-6. An ink tank for storing ink;
An ink head for ejecting ink;
An introduction flow path having a first end connected to the ink tank and a second end;
An upstream flow path having a first end connected to the second end of the introduction flow path and a second end connected to the ink head;
A downstream channel having a first end connected to the ink head and a second end connected to the second end of the introduction channel and the first end of the upstream channel;
An upstream pump provided in the upstream flow path;
A downstream pump provided in the downstream channel;
With
The upstream pump and the downstream pump are diaphragm pumps according to any one of claims 1 to 7,
Ink supply system. The ink supply system according to claim 8.
Inkjet printer.

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